Repair crews are working around the clock to restore electricity to more than 500,000 households in Ontario and Quebec after an ice storm snapped branches, brought down power lines and crimped travel in Canada ’s two most populous provinces. More than 400 flights were canceled yesterday at Toronto’s Pearson International Airport, according to the airport’s website , with dozens more scrapped in Ottawa and Montreal . The storm left up to 30 millimeters (1.2 inches) of ice in the Toronto area and may dump as much as 10 millimeters in southeastern Quebec today, Environment Canada said. In Toronto, Canada’s biggest city, about 264,000 Toronto Hydro customers were without power as of 8:42 p.m. local time yesterday, the utility said in a message on Twitter. All streetcar service in the city — on what would have been one of the year’s busiest shopping days — was suspended due to icy […]